by Chris Chase, USA TODAY Sports

by Chris Chase, USA TODAY Sports

The San Francisco 49ers opened as five-point favorites over the Baltimore Ravens in Super Bowl XLVII, but the line quickly shifted to -4, according to Covers.com.

Baltimore advanced to the Super Bowl after a 28-13 upset win over the New England Patriots. The Ravens entered the game as 9.5-point underdogs. They won their divisional playoff game in Denver facing the same steep odds.

The 49ers defeated the Atlanta Falcons earlier on Sunday to win the NFC championship.

This is the 10th time in the past 11 years that the spread for the NFL's title game is a touchdown or less.

San Francisco is making its sixth Super Bowl appearance. The team is 5-0 in those games. No other franchise with more than one appearance has an undefeated record in the game.

The 49ers were favored in each of its previous trips. The 18.5-point spread in their last Super Bowl remains the biggest in history. Steve Young and company covered that year, defeating the San Diego Chargers by 23 points.

Baltimore will make a Super Bowl appearance for the second time. When Ray Lewis won MVP honors in 2000, the team entered as three-point favorites.

Various reports said San Francisco would have been 1.5-point underdogs if New England had won the AFC championship.

The early over/under for the game is 50.

San Francisco opened the season as 17-1 favorites to win the Super Bowl. Baltimore was 14-1.